ALTER DATABASE MOUNT;

ALTER DATABASE OPEN;

2．如果是使用LGWR传递redo数据，那么执行以下命令：

检查是否有gap archive

SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

如果有则register

ALTER DATABASE REGISTER PHYSICAL LOGFILE 'filespec1';

如果是由于网络问题而导致需要切换，那么通常standby端的RFS进程并不会意识到primary已经不可访问，所以RFS进程也不会释放当前的standby redo log文件。

如果是primary端的数据库实例由于故障中断，那么一般情况下standby端的RFS进程会立刻意识到primary已经不可访问，也就会立刻释放当前的standby redo log文件。

只要RFS进程没有释放standby redo log文件，那么执行ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH命令就会在alertlog文件中发现如下的报错信息

Warning: log 4 of thread 1 is being archived or modified

Recovery interrupted.

Media Recovery failed with error 261

如果在报上述错误的时候，执行SWITCH，那么将会出现下面的错误：

ORA-16139: media recovery required

所以必须检查alertlog文件，直到发现如下信息才表示RFS进程已经释放了standby redo log文件，这时候才可以作FINISH：

RFS: Possible network disconnect with primary database

促使RFS进程释放standby redo log 文件有两种方法：

1． 等待RFS进程的network timeout，通常需要等待8分钟左右

2． 关闭standby数据库，再重新开启，这样会强制RFS进程释放standby redo log

我们可以通过v$managed_standby视图来监控RFS进程何时释放

实行Failover：

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH;

alertlog中将显示如下信息，表示finish成功：

Terminal Incomplete Recovery: UNTIL CHANGE 3738452

Terminal Incomplete Recovery: End-Of-Redo log allocation

Terminal Incomplete Recovery: log 4 reserved for thread 1 seq# 8772

TERMINAL RECOVERY changing datafile format version from 8.0.0.0.0 to

9.0.0.0.0

Switching logfile format version from 8.0.0.0.0 to 9.0.0.0.0

Terminal Incomplete Recovery: clearing standby redo logs.

Terminal Incomplete Recovery: thread 1 seq# 8772 redo required

Terminal Incomplete Recovery: End-Of-Redo log /global/oradata/ctsdb/stdby_redo04.log

Identified end-of-REDO for thread 1 sequence 8772

Terminal Incomplete Recovery: end checkpoint SCN 3738453

Media Recovery Complete

Switching logfile format version from 9.0.0.0.0 to 8.0.0.0.0

Terminal Incomplete Recovery: successful completion

Begin: Wait for standby logfiles to be archived

Wed Sep 1 13:42:28 2004

ARC1: Evaluating archive log 4 thread 1 sequence 8772

Wed Sep 1 13:42:28 2004

ARC0: Evaluating archive log 4 thread 1 sequence 8772

Wed Sep 1 13:42:28 2004

ARC1: Beginning to archive log 4 thread 1 sequence 8772

Wed Sep 1 13:42:28 2004

ARC0: Unable to archive log 4 thread 1 sequence 8772

Wed Sep 1 13:42:28 2004

Creating archive destination LOG_ARCHIVE_DEST_1: '/global/oradata/ctsdb/archive/arch1_8772.log'

Wed Sep 1 13:42:28 2004

Log actively being archived by another process

Wed Sep 1 13:42:28 2004

ARC1: Completed archiving log 4 thread 1 sequence 8772

Wed Sep 1 13:42:43 2004

End: All standby logfiles have been archived

Resetting standby activation ID 4038461969 (0xf0b60a11)

Completed: ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH

FINSH成功之后再执行SWITCH：

ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;

SWITCH成功之后，重新启动数据库：

SHUTDOWN IMMEDIATE;

STARTUP;

使用Data Guard Broker

创建Management Server repository：

emca

启动Management Server：

oemctl start oms

检查Management Server状态：

oemctl status oms sysman/oem_temp@bftest

启动Intelligent Agent：

agentctl start agent

如果启动agent报错，则检查相应的log文件，如果log文件中有如下错误：

Failed while initializing user subsystem

Error initializing subsystems

nmiumini_initializeUM: Unable to initialize UQAgent

则进行如下操作之后，重新启动agent：

rm $ORACLE_HOME/network/agent/*.q

alter system set resource_manager_plan='SYSTEM_PLAN' scope=both;

在所有站点上将BROKER启动。

SQL> ALTER SYSTEM SET DG_BROKER_START=TRUE SCOPE=BOTH;

System altered.

SQL> SHOW PARAMETER DG_BROKER_START

NAME TYPE VALUE

------------------------------------

dg_broker_start boolean TRUE

连接Data Guard Manager，必须使用具有sysdba权限的用户连接到Primary库上

>dgmgrl

DGMGRL> connect sys/dba

创建配置方案

DGMGRL> CREATE CONFIGURATION 'cts' AS

PRIMARY SITE IS 'bftest'

RESOURCE IS 'ctsdb'

HOSTNAME IS 'bftest'

INSTANCE NAME IS 'ctsdb'

SERVICE NAME IS 'ctsdb.primary'

SITE IS MAINTAINED AS PHYSICAL;

创建备用站点方案

DGMGRL> CREATE SITE 'report'

RESOURCE IS 'ctsdb'

HOSTNAME IS 'report'

INSTANCE NAME IS 'ctsdb'

SERVICE NAME IS 'ctsdb.standby'

SITE IS MAINTAINED AS PHYSICAL;

激活配置方案

DGMGRL> ENABLE CONFIGURATION;

激活资源

DGMGRL> ENABLE RESOURCE 'ctsdb';

资源的日志传送模式必须和Primary库的数据保护模式相匹配，比如数据保护模式是maximize availability，那么需要配置资源的LogXptMode属性为SYNC方式。

DGMGRL>ALTER RESOURCE 'ctsdb' ON SITE 'Boston' SET PROPERTY LogXptMode=SYNC;

DGMGRL>ALTER RESOURCE 'report_db' ON SITE 'Beijing' SET PROPERTY LogXptMode=SYNC;

DGMGRL> ALTER CONFIGURATION SET PROTECTION MODE AS MAXAVAILABILITY;

查看资源情况

DGMGRL> show resource verbose 'ctsdb';

查看某个节点上资源中的某一属性

DGMGRL> show resource verbose 'ctsdb' 'LogXptMode' on site 'Boston';

DGMGRL> SHOW RESOURCE 'ctsdb' LogXptStatus;

查看Broker的日志

DGMGRL> show log latest on site 'Boston';

查看数据库告警日志

DGMGRL> show log alert latest on site 'Boston';

查看资源的各种属性

DGMGRL> SHOW RESOURCE 'ctsdb' SendQEntries;

DGMGRL> SHOW RESOURCE 'report_db' SbyLogQueue;

DGMGRL> show resource verbose 'ctsdb' InconsistentLogXptProps;

修改资源属性，将自动修改数据库的相应初始化参数

DGMGRL> ALTER RESOURCE product_db on site v280 SET PROPERTY StandbyArchiveDest = '/global/oradata/ctsdb/archive';

Property "standbyarchivedest" updated.

DGMGRL> ALTER RESOURCE product_db on site v280 SET PROPERTY StandbyFileManagement = 'AUTO';

Property "standbyfilemanagement" updated.

DGMGRL> ALTER RESOURCE product_db on site v280 SET PROPERTY ArchiveLagTarget = '3600';

Property "archivelagtarget" updated.

停止Data Guard环境中的某个节点

DGMGRL> ALTER RESOURCE 'report_db' ON SITE 'Beijing' SET STATE='offline';

启动Data Guard环境中的某个节点

DGMGRL> ALTER RESOURCE 'report_db' ON SITE 'Beijing' SET STATE='LOGICAL-APPLY-ON';

修改 Data Guard环境中的某个节点的状态

DGMGRL> ALTER RESOURCE 'report_db' ON SITE 'v480' SET STATE='READ-ONLY';

先停止连接到备用库上的所有连接

DGMGRL> ALTER RESOURCE 'report_db' ON SITE 'v480' SET STATE='PHYSICAL-APPLY-ON';

停止Broker

SQL> ALTER SYSTEM SET DG_BROKER_START=FALSE;

作Switchover

DGMGRL> SWITCHOVER TO 'v480';

然后关闭Pirmary和Standby，重新启动

七．在Cluster环境中的主备切换步骤

在应用中cluster环境是很常见的，下面简单介绍一下在Sun Cluster 3.0的环境中，如果作Data Guard主备数据库的Switchover工作。

1．由于Cluster环境的监控，我们要手动关闭数据库的话，必须先关闭cluster，单独起一个节点的oracle。其中listener.ora.sigle的配置文件是预先写好的监听配置，主要不同是用主机的真实IP替换原先Cluster环境中的虚拟IP。

/usr/cluster/bin/scswitch -F -g oracle-rg

mount /global/oradata

cd /export/home/oracle/app/oracle/product/9.2.0/network/admin

cp listener.ora.sigle listener.ora

lsnrctl start